Channels

Services

Vulnerability in OpenSSL 1.0.x

Security expert Georgi Guninski has pointed out a security issue in the 1.0 branch of OpenSSL that potentially allows SSL servers to compromise clients. Apparently the hole can be exploited simply by sending a specially crafted certificate to the client, causing deallocated memory to be accessed in the ssl3_get_key_exchange function (in ssl\s3_clnt.c). While this usually only causes an application to crash, it can potentially also be exploited to execute injected code.

Guninski included a certificate and a flawed key for recreating the problem in the report he released on the Full Disclosure mailing list. When tested briefly by the The H's associates at heise Security on an current Ubuntu 10.04 system with OpenSSL 0.9.8k, a certificate belonging to an RSA key of only 4006 bits in length (and where q is not prime) only produced a warning that the certificate was flawed.

As virtually none of the Linux distributions use OpenSSL 1.0.x, the hole is unlikely to create major concerns. An update has yet to be released by the OpenSSL developers, but the issue is already being discussed on the OpenSSL developer mailing list.